Motion system

Purpose

• Provide precise, repeatable axis motion

• Keep motion execution simple and robust in the initial build

• Allow future upgrades without redesigning the machine structure

Current motion configuration

• Motion controller:

  • Duet 3 6HC

• Motors:

  • stepper motors on all linear axes

• Motor drive:

  • steppers driven directly by Duet

• Mechanical transmission:

  • HTD belt between motor and leadscrew

• Purpose of belt coupling:

  • mechanical filtering of motor vibration

  • increased effective steps per millimeter

  • flexibility in gear ratio selection

• Leadscrews:

  • directly coupled to axis motion

• Feedback:

  • open-loop stepper operation in current phase

Design considerations

• Motion system prioritized for:

  • simplicity

  • predictability

  • compatibility with supervision layer

• Motion execution kept independent from:

  • adaptive supervision logic

  • compliance estimation

• Any feed or spindle adaptation performed via:

  • Duet macros

  • supervisory requests only

Deferred motion upgrades

• Closed-loop servo drives

• Dual-loop control using external feedback

• Glass scale integration

• Custom servo inverter development

Scope limitations

• No real-time modification of trajectories by ECU

• No active damping or compensation within motion controller

• Motion system behavior assumed deterministic for supervision purposes